Vitamin D supplements lower risk of autoimmune disease: study

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Vitamin D supplements lower risk of autoimmune disease: study

Washington, US January 27 ANI According to a study, daily vitamin D supplements - or a combination of vitamin D and omega-3 fish oil - appears to carry a lower risk of developing autoimmune disease, with a more pronounced effect after two years.

The researchers said that the clinical importance of these findings is high, given that these are well-tolerated, non-toxic supplements, and there are no other known effective therapies to reduce the rates of autoimmune diseases. Autoimmune disease occurs when the body's defence system mistakenly attacks normal cells. Common conditions include rheumatoid arthritis, psoriasis, and thyroid diseases, which increase with age, particularly among women.

Both vitamin D and omega-3 fatty acids from seafood are known to have a beneficial effect on inflammation and immunity, but no large randomised trials have shown that these supplements can lower the risk of autoimmune disease.

The researchers tried to find out the effects of vitamin D and omega-3 fish oil supplements on the rates of autoimmune diseases in 25,871 US adults in 25,871 US adults, average age 67; 51 per cent women, and 71 per cent non-Hispanic white. Blood levels of vitamin D and omega-3 fatty acids were also measured.

Participants were randomly allocated to receive vitamin D 2,000 IU day or matched placebo, omega 3 fatty acids 1,000 mg day or matched placebo, and were asked to report any diagnosed autoimmune disease over an average 5.3 year period.

These included rheumatoid arthritis, polymyalgia rheumatica pain and stiffness in the muscles around shoulders, neck and hips thyroid disease, and psoriasis, among others.

Medical records show that there were reports of cases. Those with insufficient documentation for certainty were classed as probable cases.

A confirmed autoimmune disease was diagnosed in 123 participants in the vitamin D group over the full duration of the trial, compared to 155 in the placebo group - a 22 per cent lower relative rate.

In the omega-3 fatty acid group, 130 confirmed cases were diagnosed compared with 148 in the placebo group, a 15 per cent reduction, but this was not a statistically significant result.

When probable cases were included, omega 3 fatty acid supplements significantly reduced the rate by 18 per cent compared to placebo and there was an interaction with time, indicating a stronger effect the longer the supplements were taken.

When only the last three years of the trial were considered, similar results were found. The vitamin D group had 39 per cent fewer confirmed cases than placebo, while the omega-3 fatty acid group had 10 per cent fewer confirmed cases than placebo. Vitamin D and Omega 3 fatty acid supplements decreased autoimmune disease by about 30 per cent compared to placebo alone.

This was a large trial involving a broad population with high follow-up and adherence to treatment. The researchers acknowledged that they only tested one dose and formulation of each supplement, but they also said that the results may not apply to younger individuals.

They said that this is the first direct evidence that daily supplementation with either agent or a combination of vitamin D and omega-3 fatty acid can reduce autoimmune disease incidence among older US adults for five years, with more pronounced effects after two years of supplementation.

They said that they were continuing to follow participants in an extension study for two years to test the time course of this autoimmune disease reduction effect.